public class Puppy {
    private int puppyAge;

    public Puppy(String name){
        System.out.println("小狗的名字是：" + name);
    }

    public void setAge(int age){
        puppyAge = age;
    }

    public int getAge(){
        System.out.println("小狗的年龄为：" + puppyAge);
        return puppyAge;
    }

    public static void main(String[] args) {
        Puppy myPuppy = new Puppy("tommy");
        myPuppy.setAge(2);
        System.out.println(myPuppy.getAge());

        myPuppy.puppyAge = 1; // 依然是类内的
    }
}